For the comparison, methods FGAMM and varEM (“varEM 2.1”) are based on function register_fpca
in version 2.1.5 of the registr
package, which uses methods from packages gamm4
[1]} (v0.2.7) and lme4 [2]} (v1.1.26).
These methods are compared to the old version of registr (v1.0.0,
based on gamm4 v0.2.6 and lme4 v1.1.23),
which does not contain the algorithmic improvements outlined in Appendix A1.
We also compare our methods to function align_fPCA of package fdasrvf
[3]} (v1.9.4) which implements the joint SRVF approach.
All methods except version 1.0 of package registr (“varEM 1.0”)
were run in parallel mode using ten cores.
